Process of making printing plates



oct 3, 1944' i F. E. REL-LY ETAL 2,359,385

PROCESS OF MAKING PRINTING PLATES Filed May 20, 1941 s sheetssheet 1PR/NT/NG `SURFACE TH//v CCPPER E/ ECTRCTYPE l A (FROM EAU of? wnx Mom)(CUETER Mfg /Zkvf I ff J J v Y l. (/4 VACUUM CHUCK f l /4 l soFT MET/Ll.OVER/.AY

VACUUM CHUCK CRV/Lam MU'NIW v-RNEYS Oct- 3, 1944 F. E. REILLY x-:TAL2,359,385

PROCESS OF MAKING PRINTING PLATES Filed May 2o, 1941 s sheets-sheet 2RuTz-:D our TYPE MATTER Mgg TME Fu/ L To/vE r Fuu. ToNE @6' i f f7 L /W,/Y//

3 BUFFED SURFACE ./0 ROL/TED OUT A a.; 40 @ya caFPER ELEc/forff PRINT/NqSURFACE ATTO R N EYS 06f 3, l944 F. E. REILLY ET L 2,359,385

PROCESS OF MAKING PRNTING PLATES Filed May 20, 1941 3 Sheets-Shea?I 3DUMMY BASE l COOL/)NT .iP/NZ E f4 F OIL.

ELECT/@TYPE LE ELE/cT/TOTYPE f [j D c, DEAD METAL UQSXg DROP/25D ourELECTAUTYPE -f DEAD MET/4L REAS REMOVED BY OUTLINE /JOL/T/Mcr` WATTORNEYS Patented Oct. 3, 1944 PROCESS F MAKING PRINTING PLATES FrankE. Reilly, Chicago, and Chester Holsinger, River Forest, Ill., assignorsto Electrographic Corporation, New York, N. Y, a corporation of DelawareApplication May 20, 1941, Serial No. 394,262

9 Claims.

The present invention relates to a novel and improved process ofproducing printing plates, particularly curved or parti-cylindricalelectrotypes, as well as the novel electrotype produced by such process.

Objects and advantages of the invention will be set forth in parthereinafter and in part will be obvious herefrom, or may be learned bypractice with the invention, the same being realized and attained bymeans of the instrumentalities and combinations pointed out in theappended claims.

The invention consists in the novel parts, constructions, arrangements,combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a parthereof, illustrate one embodiment of the invention, and together withthe description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a diagrammatic sectional view showing a thin relativelyflexible electrotype in accordance with the present invention;

Figure 2 is a diagrammatic View showing the cutting operation by whichthe electrotype is re duced in thickness and provided with a relativelsmooth back;

Figure 3 is a diagrammatic sectional View illustrating the bumping ormaking-ready of the electrotype in accordance with the present in-Figure 4 is a diagrammatic sectional View showing the thin electrotypewith its soft metal overlay still in place;

Figure 5 is a diagrammatic sectional view showing a further cuttingoperation by which the back of the made-ready plate is smooth;

Figure 6 is an exaggerated diagrammatic fragmentary section of themade-ready and partially routed plate;

Figure 7 is a top plan view showing the madeready and partially routedplace in accordance with the present invention;

Figure 8 shows an end view of the plate of Figure 7 bent to the generalcurvature desired;

Figure 9 is a back View of the plate shown in Figures '7 and 8 withlow-fusing alloy foil applied to certain portions of its back;

Figure 10 is a diagrammatic sectional view taken on the line Ill-l0 ofFigure 9 and showing the foil applied to certain areas of the plateback;

Figure 11 is a perspective view showing a turtle -or dummy-base for usein connection with the present invention;

(Cl. lOl-401.1)

Figure 12 is a diagrammatic sectional view showing the apparatus formounting the thin electrotype on its curved base or turtle;

Figure 13 is a top plan view of the plate secured to its turtle or base,and with the routing completed for removal of the dead metal ornonprinting areas; and

Figure 14 is a sectional view taken on the line l4-I4 of Figure 13 andshowing the plate secured to its turtle and with the dead metal areasdropped out.

The present invention has for its object the provision of a novel andimproved printing plate particularly adapted for use in color printing,as well as the provision of a novel and improved process for theproduction of curved electrotypes for high quality letterpress printing,particularly in multicolor. A further object of the invention is theprovision of a novel and improved electrotype which has exceptionalwearing qualities, which can be prepared for printing prior to beingplaced on the cylinders of the printing press, and which has relativelylittle stretch from the time it is removed from the electrotyping caseuntil it is completely prepared for printing on the press. The inventionalso provides a novel and improved process of preparing curvedelectrotypes in which the plate as it is mounted on the press hassubstantially the same dimensions as the original photoengraving fromwhich it was made, thereby simplifying and rendering more accurate theregister of four color process plates.

Still another object of the invention is the provision of a novel andimproved electrotype vwhich does not require underlays or overlaysduring printing, and in which the register of the several electrotypesis accurately predetermined prior to the plating of the press, therebyreducing the time required for the plating of the press.

Heretofore, in the printing of curved electrotypes it has almostuniversally been the custom vto prepare the electrotypes in flat form,to remove the electrotype shell from the case, to back the electrotypeshell with lead or other alloy and then to shave or otherwise surfacethe back of the shell and alloy, after which the llat surfaced andbacked electrotype shell is bent to the desired curvature so that itwill accommodate itself to the surface of the printing cylinder to whichit is to be clamped.

This usual process requires a great amount of care and a high degree ofskill, inasmuch as the `plate stretches unequally during the bendingoperation, the solid printing areas stretching differently from the deador non-printing areas,

and the copper shell stretching differently from the dead ornon-printing areas, and the copper shell stretching differently from thelead or alloy backing. Inasmuch as a set of multicolor plates arenecessarily different from each other, this amount of stretch isdifferent for each of the several plates of each set, and it is onlywith the greatest exercise of care and skill that commerciallysatisfactory register is obtained between the plates. Furthermore, theprinting surface is frequently damaged during the bending operation, andeven where make-ready is incorporated in the plates, as by bumping or bythe McKee process, the electrotype is still relatively soft due to thelarge thickness of lead or alloy with which it is backed, and theprinting characteristics of the plate change during a long press run.

Another disadvantage which has heretofore existed in connection with theuse of curved electrotypes, is theA fact that frequently the curvatureof the electrotype is not exactly uniform nor is it exactly the same asthe curvature of the printing cylinder on which it is to be mounted withthe result that the plate must be warped as it is clamped to thecylinder and the plate may rock very slightly during the printingoperation. The back of the plate, being of lead or other alloy, hasrelatively little strength, and is readily subject to crystallization,so that frequently during the printing operation the plates are thrownfrom the printing cylinder creating a hazard for the workman as well asbeing capable of causing serious damage to the printing mechanism.

All of the foregoing and other disadvantages are avoided by the processand plate of the present invention. In accordance with the process ofthe present invention, an electrotype mold is prepared in a conventionalmanner from whatever type, photoengravings or other matter is to `bereproduced. This mold is electro-deposited in the usual electrotypingmanner until the mold has been coated substantially uniformlyV to athickness slightly in excess of 0.045 inch. When this electrotypingoperation has been completed, the electrotype l is stripped from themold and is placed on a rigid flat vacuum chuck I4, where it is held bysuction while the black is milled by cutter I2, or otherwise cut andsmoothed, to reduce the thickness ,of the plate to between approximately0.020 and 0.0401116111.

This` surfaced, relatively thin electrotype is then provided with aregistering underlay I8 of conventional form attached to its back and isplaced fa-ce up on the platen I6 of a hydraulic press, after which theface of the electrotype is covered with a thin sheet of relatively softmetal over which is laid a relatively thick layer of resilient packing22 such as a large number of sheets of newsprint. The ram 24 of thehydraulic press is then lowered and powerful pressure is applied to theassembled electrotype, underlay, overlay and packing, conforming theelectrotype to the underlay and embossing the soft metal overlay.

When this operation lhas been completed, the thin electrotype and itssoft metal overlay are removed from the hydraulic press and are placedon a cutting or surfacing apparatus where the plate and its soft metaloverlay are placed on the vacuum chuck I4, with the overlay 20 beneaththe plate I0 and between the plate I0 and the surface of the chuck I4.The plate is then given a finishing cut by means of the fine cutter 26on its back so as to render the back smooth and to remove anyinequalities caused by the hydraulic pressing operation, as well as toremove the roughness left by the rst cutting operation.

When the plate has been thus made ready, the

edges of the plate l0 are accurately trimmed to the desired size, thesoft metal overlay 20 is removed from the printing face, and While theplate is still flat, the small areas 3B which are not to print arecarefully routed, such as the spaces between the columns as well as thespaces between some of the larger letters. Thereafter the plate I isbent, manually or otherwise, so as to conform it to the generalcurvature required, and due to its extreme thinness this can easily beaccomplished.

We have found by actual experience that the bending of a plate which is0.040 inch in thickness and is to be tted to a cylinder having fourplates around, does not stretch more than approximately 0.015 inch,which is an insignificant amount, and differences in the stretch ofvarious plates amount to only a few thousandths of an inch, so thatcommercially perfect register is uniformly obtained.

The partially routed, preliminary bent thin electrotype which has beenmade ready is then placed with its face down and its smooth back iscoated with soldering flux, after which the back of the plate is coveredwith an exceedingly thin sheet 4| of a low fusing alloy foil oversubstantially its entire surface, excepting only any relatively largedead or non-printing areas 39.

In routing the dead areas 39, they are preferably left attached to themain portions of the plate by means of joiners until after the plate hasbeen soldered to its base 49, after which these dead areas 39 may beremoved by routing or cutting through these joiners thereby detachingthe dead areas from the remainder of the plate.

The plate thus prepared for soldering is then accurately registered withrespect to its turtle or dummy base 49, which is a smooth accuratelymachined parti-cylindrical member, and usually of the same size as thethin electrotype, is of considerable thickness so as to be quite rigid,and is preferably formed of some dense, strong material which can besoldered and re-used, such as brass or bronze. The thickness of theturtle 49 is such that combined with the plate l0 to be attached to it,they will be of proper thickness for the rotary press on which they areto be printed. The plate and its turtle which has been previouslyfluxed, are then placed in a mounting apparatus which comprises aconcave member 50 conforming in curvature to the desired curvature ofthe finished plates and a convex member 5| of the same curvature as theprinting cylinder. While the plate I0 and its turtle 49 are securelyclamped between the concave and convex members 50 and 5I, the plate andturtle are heated by gas flames 52 slightly above the melting point ofthe solder foil 4I, and are then cooled by water or other cooling mediumto set the solder, after which they are removed from the mountingapparatus with the plate securely fastened to its turtle in a definitepredetermined position, insuring accurate register.

If the plate contains any dead metal or relatively large non-printingareas, such as 39, the plate and its turtle are placed on a curvedrouting machine, these dead metal areas 39 are outlined in the router,the router cutting entirely -through the plate so that the dead metalareas drop out on removal of the plate from the IOuting machine.

Thus, there is produced a novel and improved 'electrotype which is ofsubstantially the same dimensions as the original from which it wasmade, Vthe electrotype and its back are relatively dense, and there isno appreciable thickness of soft metal which can yield during theprinting operation, the makeready necessary for proper printing isaccurately incorporated into the plate itself, and the assembled plateand turtle are completely ready to go on the press with the assurancethat the mere clamping of the turtlemounted plate in a predeterminedposition on the printing cylinder will result in accurate register,thereby eliminating most make-ready and -registering operations of thepress, with result- .ant saving in press time.

The foregoing general description is the preferred process of carryingout the present invention, but certain of the steps may be modied oromitted without impairing the usefulness of the Vprocess as a whole, andwith a consequent partial achievement of the various benefits of thepresent invention.

Referring now in detail to certain Iof the steps -of the presentinvention, the lead or wax mold from which the electrotypes are to beproduced,

may, if desired, be given a preliminary flash coat or electrolyticdeposit of nickel if steel-faced `electrotypes are desired, andthereafter the cop- -per electrotype is deposited on the mold.

While various electrotyping baths may be used,

We find it advisable to control the rate of deposit,

and the composition of the bath, in known manners so as to produce arelatively dense, hard,

vlong wearing copper deposit of relatively great strength which ispreferably from 0.020`to 0.045 inch in thickness. In certain instancesit is possible to use even thinner deposits, but generally they do notprovide suilicient strength, while in .other instances it may bepossible to use thicker deposits but the thicker the deposit the greaterthe stretch of the plate during the curving operation.

During the first cutting operation, the thin .eleetrotype I is placedwith its face down against the vacuum chuck I4, and the-cutter I2 andchuck I4 are moved relatively to each other at a relatively slow speedWhile the plate is securely held to the chuck by vacuum. In order toimprove the security of the holding, the plate is preferably formed witha -continuous bearer com- .pletely outlining the printing portion of theplate, .thereby providing a uniform flat surface which will accuratelyseat against the chuck and prevent leakage of air beneath the plate.

The underlay I8 utilized, in case it is desired `to incorporate themake-ready into the plate, kalthough it is not essential, may be eitheren..

gravers underlay, or a press underlay, and is of vvarying thickness, thethicker portions lying immediately under the parts of the plate whichare Ito print the most ink. Thus, in an illustration,

the full tones might be underlaid with paper of the thickness of 0.004,the half tones with an underlay having the thickness of 0.002", and

the highlights might have all the underlay omit- 4ted. The soft metaloverlay 20 provided 0n the sheets of newsprint, the soft metal overlay20 being ofapproximately the same size as the thin .copper electrotype,while the resilient packing I8 is of slightly larger area.

During the finishing cutting operations, where the back of the plate ismilled or otherwise surfaced to remove the portions of the back of theplate raised during the makeready on the hydraulic press, the cutter 26preferably travels diagonally of the plate l0, the cutting operationbeing carried out with the soft metal overlay 20 still adheringto theface of the plate, preferably without having been removed therefrom.

Figures 6 and 7 of the drawings show the thin electrotype after it hasbeen made ready, finally surfaced on its back, and partially routed, andin these figures the thin electrotype I0 is shown as provided with ailat, smooth back 30, with type matter 3| on its face, and withvarioushalftone parts also on its face. The half-tones of the illustrations areshown at 33 andare raised sightly above the level of the type matter soas to exert somewhat more pressure during the printing operation, whilethe full tones 34 are raised even more to exert still greater pressure.The yhighlights 35 in the illustrations may be the same height as thetype matter, or otherwise as determined by the underlay employed. Atcertain places, such as 38, some of the smaller non-printing areas ofthe plate have been routed out, while other large non-printing areas 39are later cut apart so that the metal may be completely removed.

In order to facilitate accurate register, the plate is convenientlyprovided with conventional register marks 40, incorporated inthe platefrom which the electrotype was reproduced, these register marks Ibeingaccurately located with respect to each other. The plate is trimmed, toremove the bearers, and this trimming is carried out carefully so thatthe edges of the plate have a predetermined relation to the registermarks, and accurately correspond with the dimensions of the turtle,thereby enabling the plate to be placed on the turtle, its edgesregistered with the edges of the turtle, thereby insuring ,accurateregister of the several plates on their respective turtles.

In case greater accuracy in register is required, the plate lll may beprovided at its ends with relatively small drilled holes 42 which areaccurately spaced with reference to the register marks 40, and are sospaced with respect to each other and the printing surface that theycorrespond exactly to similar holes 46 formed in the-turtle, therebyenabling the plate to be accurately positioned on the turtle during thesweating or soldering operation by means of locating pins 41.

Any suitable or desired flux may be employed for the back of the plateI0 and the face of the Vturtle 49, but preferably the flux is acompletely volatile type so that no solid residue remains Which mightshow through or deforrn the relatively exible thin electrotype.Preferably, the sheet of low fusing alloy foil is less than 0.001 inchthickness, and may conveniently vbe of equal parts of tin and lead. Thissheet of solder foil 4| is placed over the entire back of the plate I0,excepting only those parts corresponding to dead metal or non-printingareas 39 which are not to be soldered to the base.

The turtle or dummy -base 49 comprises an ar- ;cuate vorparti-cylindrical member, accurately corresponding to the surfacepf theprinting cylinder and may -be formed with slightly beveled edges bywhich it may be gripped by the plate securing clamp on the printingcylinder. Near its ends, the base 49 is provided with holes 46 toreceive registering dowel pins 41 which also pass through holes 42 inthe plate l0 and accurately register the plate or its base duringsoldering.

The plate I is accurately registered on its base 49 and the two are thenplaced in the saddle 50, pressure is applied by the convex member I andthe plate is heated just above the melting point of the solder Aby meansof the heaters 52 thereby sweating the plate ID to its base, after whichcooling water is iiowed through pipes 54 and back 5| to set the solderquickly.

The dead metal areas 39 may then be outlined by routing and when thishas been completed, the dead metal drops out leaving the base 49 visibleand increasing the depth of the areas.

Certain features of the invention are useful in connection With theproduction of flat printing plates, for instance, Where a made-readyelectrotype formed of dense metal is required for printing.

The invention in its broader aspects is not limited to the specicmechanisms shown and described but departures may be made therefromwithin the scope of the accompanying claims without departing from theprinciples of the invention and without sacricing its chief advantages.

What we claim is:

1. A process of producing a curved printing plate which comprisescutting the back of a thick electro-deposited plate to reduce itsthickness and provide a smooth, flat back, routing the at plate,applying thin solder foil to the back of the plate, forming registerholes in the margins of the plate, applying the plate to a thick curvedbase having similar register holes, heating the plate to solder theplate to the base, and lcutting around dead metal areas to drop out thedead metal from the Icompleted plate.

2. A process of producing a curved printing plate which comprisescutting the back of a thick electro-deposited plate to reduce itsthickness and provide a smooth, flat back, providing said plate with anunderlay and a soft metal overlay, powerfully pressing said platebetween the underlay and overlay to raise the heavier printing portionsof the plate, again cutting the back of the plate with its overlay inplace to smooth the back of the plate, routing the flat plate, applyingthin solder foil to the back of the plate, applying the plate to a thickcurved base, heating the plate to solder the plate to the base; andcutting around dead metal areas to drop out the dead metal from theIcompleted plate.

3. A process of producing a curved printing plate which comprisescutting the back of a thick electro-deposited plate to reduce itsthickness and provide a smooth, fiat back, routing the flat plate,applying thin solder foil to the back of the plate, applying the plateto a thick curved base, heating the plate to solder the plate to thebase, and cutting around dead metal areas to drop out the dead metalfrom the completed plate.

4. A process of Iproducing a curved printing plate which comprises[cutting the back of a thick electro-deposited plate to reduce itsthickness and provide a smooth, flat back, providing said plate with anunderlay and a soft metal overlay, powerfullypressing said plate betweenthe underlay and overlay to raise the heavier areas.

printing portions of the plate, again cutting the back of the plate withits overlay in place to smooth the back of the plate, routing the fiatplate, applying thin solder foil to the back of the lplate, formingregister holes in the margins of the plate, applying the plate to athick curved base having similar register holes, heating the plate tosolder the plate to the base, and cutting around dead metal areas todrop out the dead metal from the completed plate.

5. A process of producing a printing plate which comprises cutting theback of a thick electro-deposited plate to reduce its thickness andprovide a smooth, nat back, providing said plate with an underlay and asoft metal overlay, powerfully [pressing said plate between the underlayand overlay to raise the heavier printing portions of the plate, againcutting the back of the plate with its overlay in place to smooth theback of the plate, routing the fiat plate, applying thin solder foil tothe back of the plate, forming register holes in the margins of theplate, applying the plate to a thick base having similar register holes,heating the plate to solder the plate to the base, and cutting arounddead metal areas to drop out the dead metal from the completed plate.

6. A process of 4producing a printing plate which comprises cutting theback of a thick electro-deposited plate to reduce its thickness andprovide a smooth, at back, routing the flat plate, applying thin solderfoil to the back of the plate, applying the plate to a thick base,heating the plate to solder the plate to the base, and cutting arounddead metal areas to drop out the dead metal from the completed plate.

7. A process of producing a printing plate which comprises cutting theback of a thick electro-deposited plate to reduce its thickness andprovide a smooth, flat back, routing the flat plate,

Ywith an underlay and a soft metal overlay, powerfully pressing saidplate between the underlay and overlay to raise the heavier printingportions of the plate, again cutting the back of the plate With itsoverlay in place to smooth the back of the plate, routing the flatplate, applying thin solder foil to the back of the plate, applying theplate to a tlrick base, heating the plate to solder the plate to thebase, anad cutting around dead metal areas to drop out the dead metalfrom the completed plate.

9. A process of producing curved printing plates including cutting theback of an electrodeposited plate and provide a smooth, fiat back,thickness, routing said plate while it is flat, routing around deadmetal areas 1in the plate but leaving joiners connecting the dead metalareas to the remainder of the plate, curving said plate, attaching itsecurely to a curved base member and cutting the joiners to remove thedead metal FRANK E. REILLY. CHESTER HOLSINGER.

